DE1087181B - Multiple push-pull modulator circuit - Google Patents

Description

GERMAN

The invention relates to a multiple push-pull modulator circuit for amplitude modulation with mutually decoupled pairs of terminals for the carrier frequency, the input characters and the output characters, wherein the circuit arrangement contains two carriers, each with two center-tapped secondary-side push-pull windings, the ends of which are connected to one another via four rectifier cells are that at the two ends of a center-tapped push-pull winding in each case similar Rectifier poles are connected to the two push-pull windings of the same transformer of different types Rectifier poles are connected and that the connections are chosen so that the Transfer from one transformer to the other transformer polarity reversal occurs when the two Push-pull windings of a transformer connected two pairs of rectifiers through the carrier current can be controlled alternately in the forward or reverse direction.

The well-known ring modulator is a six-pole, at the three pairs of terminals of the four groups of the non-linear branches Modulation products only three are accessible, while the fourth group with the main modulation product / = 0 (direct current) is short-circuited in the ring and not removed or through terminating resistors can be influenced.

The multiple push-pull modulator circuit is therefore designed according to the invention so that each of the four groups of modulation products I (gh ± ufζ), Π (ufr ± Sfζ), ΙΠ (ufj ± uf _z ) IV (gfr + gh) at a particular Terminal pair occurs, which is decoupled from the other terminal pairs by push-pull action, so that the remaining groups of modulation products are suppressed, with u odd numbers 1, 3, 5. . ., with g even numbers 0, 2, 4 .- .., with f _T the carrier frequency and with f% the symbol frequency and a third transformer for the modulation product II is provided with two secondary windings with the same number of turns, which at the center points of the four push-pull windings of the other two transformers are connected in such a way that each winding of the third transformer connects the centers of such push-pull windings of different transformers, the ends of which lead to similar rectifier poles, and that the ends of the secondary-side windings of the third transformer which are homopolar with respect to the carrier voltage are connected to the The middle of the push-pull windings of the same transformer lead and the fourth pair of terminals for group IV of the modulation products either at the center taps or at the same-pole multiple push-pull modulator circuit

Applicant:

Siemens & Halske Aktiengesellschaft,

Berlin and Munich,
Munich 2, Wittelsbacherplatz 2

Dipl.-Ing. Karl Scherer, Munich,
has been named as the inventor

Ends of the two secondary windings of the third transformer is connected and where the Modulation product I and III each to one of the two connected to the rectifiers on the secondary side Is assigned to the transformer. This results in eight-pole circuits in which all four groups of Modulation products arising in the non-linear branches at four mutually decoupled. Terminal pairs occur.

In a further embodiment of the invention, the fourth pair of terminals for group IV of the modulation products can have a real or complex resistance be completed, the z. B. can be changed over time, in particular manually or automatically is adjustable. The terminating resistor can also be designed so that it is equal to / = 0 for the frequency or approximately equal to zero or infinite or alternately switchable between the two values. It can also be used to control the transfer rate of a frequency conversion step by step or continuously A variable DC voltage can be applied to the fourth pair of terminals. Depending on the application of the multiple push-pull modulator it may also prove expedient to use resistors, in particular in parallel and / or in series with the rectifier cells to switch real resistances.

The invention is explained in more detail with reference to the exemplary embodiments shown schematically in FIGS explained.

If a non-linear circuit of currents of different frequencies, e.g. B. the symbol frequency fi and the carrier frequency / γ is flowed through, a distorted current arises due to non-linear distortion, the spectrum of which is made up of the following groups

009 587/285

made up of: (7 * = odd ' numbers: 1, 3, 5 ..., g - even numbers: 0, 2, 4 ...)

Group I:

gfr ± ^u fz containing main products: f _z
Group II:

nfr + gfz containing main products f _T
Group III:

uf _T ± ufz containing main products: fcifz
Group IV:

^ gfz containing main products: / = 0

These four subgroups each contain a main modulation product that characterizes them: the carrier frequency, the ^{symbol frequency, the side frequency and} the frequency zero (direct current). By push-pull circuits or double push-pull circuits with several, z. B. two or four non-linear branches, you can now achieve that in the outer circuits only the relevant main modulation product and the sub-spectrum of its group occurs. So z. B. in the well-known ring modulator circuit on the three pairs of terminals three separate external circuits for the partial spectra of groups I, II and III are connected, while for the spectrum of group IV (main modulation product direct current, / = 0) only one inner self-short-circuited circuit , the rectifier ring. ,

In Figs. 1 and 2 circuits are shown that were derived from the ring modulator circuit and in which a fourth outer circle with the terminals 4/4 'was created for the sub-spectrum of group IV by dividing the transformer windings into two parallel windings. The four pairs of terminals 1/1 '... 4/4' of the eight-pole modulator created in this way are all decoupled from one another in terms of frequency through a push-pull effect, i.e. if the circuit is ideally symmetrical, only a partial spectrum is created at each pair of terminals: Groups 1 to IV are attached to the terminals 1/1 'the character frequency f _z and the carrier frequency f _T at terminals 2/2', the corresponding partial spectra Γ to IV are available at terminals 1/1 '... 4/4'. So you can see the sidebands fj + fz at the clamps 3/3 '. However, the function of the modulator depends on the load on terminals 4/4 '.

In the event of a short circuit at terminals 4/4 ', the mode of operation corresponds to that of the normal ring modulator. In each carrier half-wave, the hatched rectifier cell pair G 2, G 3 or the unshaded rectifier cell pair Gl, G 4 is controlled to be transparent. The two cell pairs are connected to different transformer windings of U ₁₁₁ , but effectively parallel to the carrier source (terminals 2/2 '), whereby the two pairs are alternately controlled by the carrier current in the on or off state. As with the ring modulator, "linearization resistors" in series with the cells are advantageous, as they limit the currents in the forward direction. The resistances of the transformer windings also work in this way.

When there is no load at terminals 4/4 ', the two rectifier cells of a pair are connected in parallel for the carrier supply, but the two pairs are connected in series with different polarity. The two windings of the transformer U _{11 also} operate in series. The mode of operation is different from that of the ring modulator. Instead of "linearization resistors" in "series connection with the rectifier cells, those in parallel connection to the rectifier cells may have to be provided that limit the voltage drops across the blocking resistors of the rectifier cells.
If a voltage is applied to terminals 4/4 ', it acts in the same direction on all rectifier cells. This allows you to control the modulator properties. In particular, the degree of attenuation of the frequency conversion I / II can be continuously controlled with a direct voltage. Such facilities can ζ. Β for regulation, in particular for automatic regulation, the attenuation of TF channels or channel groups with direct or indirect control by a rectified pilot current, as a presser and as an expander circuit in TF compander systems, as a volume controller for transmitter control, as a pushbutton circuit to block channels or can be used for pulse sensing and for additional amplitude modulation (also with alternating current) of simultaneously frequency-converted oscillations.

Finally, there can also be a frequency-dependent load z. B. by a low-pass filter (in the limit series choke or parallel capacitor) or a Bandstop filter (blocking circuit or suction circuit) can be combined with a direct current control.

Claims (6)

Patent claims: 1.Multiple push-pull modulator circuit for amplitude modulation with mutually decoupled pairs of terminals for the carrier frequency, the input characters and the output characters, whereby the circuit arrangement contains two transformers (U ₁ and U ₁₁₁ ) each with two center-tapped secondary-side push-pull windings, the ends of which are connected via four rectifier cells ( Eq ... G 4) are connected to one another in such a way that. Rectifier poles of the same type are connected to the two ends of a center-tapped push-pull winding, that different types of rectifier poles are connected to the two push-pull windings of the same transformer (U ₁ and U ₁₁₁ ) and that the connections are chosen so that when transferring from one transformer to the other transformer polarity reversal occurs when the two rectifier pairs connected to the two push-pull windings of a transformer are alternately controlled by the carrier current in the forward or reverse direction, characterized by such a design that each of the core groups of modulation products I (jf _T + w / _z ), II (uf _T ± gfz), III (uf _T ± ufz), IV (gfr ^ gfz) ^on - a special pair of terminals (1/1 'or 2/2' or 3/3 'or .4 / 4 ') occurs, which is decoupled from the other pairs of terminals by push-pull action, so that the other groups of modulation products are suppressed, with u odd numbers 1, 3, 5 ..., with g even numbers 0, 2, 4 ..., with f _T the carrier frequency and with f _z the symbol frequency and a third transformer (U ₁₁ ) is provided for the modulation product II with two secondary windings with the same number of turns , which are connected to the centers of the four push-pull windings of the other two transformers (ϋχ, U ₁₁₁ ) in such a way that each winding of the third transformer (U ₁₁ ) the centers of such push-pull windings of different transformers (U ₁ , U ₁₁₁ ) with each other I Uö / löl connects, the ends of which lead to similar rectifier poles, and that the ends of the secondary-side windings of the third transformer (Ü _a ), which are homopolar with respect to the carrier voltage, lead to the centers of the push-pull windings of the same transformer and the fourth pair of terminals (4/4 ') for group IV of Modulation products are connected either to the center taps or to ends of the same polarity of the two secondary-side windings of the third transformer (Ü " _n ) and the modulation product I and III is assigned to one of the two transformers connected to the rectifiers on the secondary side (U ₁ or Um) . 2. Multiple push-pull modulator circuit according to claim 1, characterized in that the fourth Terminal pair (4/4 ') for group IV of the modulation products is closed with a real or complex resistance. 3. Mehrfacli push-pull modulator circuit according to claim 2, characterized in that the terminating resistor can be changed over time, in particular regulated manually or automatically. 4. Multiple push-pull modulator circuit according to claim 2, characterized in that the terminating resistor for the frequency f = 0 is equal to or approximately equal to zero or infinite or alternately switchable between the two values. 5. Multiple push-pull modulator circuit according to one of the preceding claims, characterized in that that to control the transfer rate of a frequency conversion one step at a time or continuously variable DC voltage is applied to the fourth pair of terminals (4/4 '). 6. Multiple push-pull modulator circuit according to one of the preceding claims, characterized in that that parallel and / or in series with the rectifier cells (Eq. ... G 4) resistors, in particular real resistors are connected. Considered publications:
Swiss patent specification No. 248 981. 1 sheet of drawings